President Barack Obama and GOP challenger Mitt Romney face off for the last time in tonight’s foreign policy debate with starkly different challenges as they near the end of their fight to be the next commander in chief.

Obama, who has seen his once-sizable lead in national polls vanish, will try to press what has been an advantage on foreign affairs to make the case that Romney’s inexperience on foreign policy risks more war, more blood and more treasure.

Romney must appear tough, but not reckless, as he squares what has been more bellicose rhetoric, particularly during the Republican primary season, with a public that has soured on foreign military engagements. And both candidates will try to pick their spots to pivot back to the issue on most voters’ minds: the economy.

War Weary

The president’s campaign in particular hopes to capitalize on the nation’s disenchantment with war.

“After a decade of war, both in Afghanistan and Iraq, the most important thing we have to do now is… bring American troops home and battle for America’s future economically,” said Chicago Mayor Rahm Emanuel, Obama’s former chief of staff, previewing the president’s message on ABC’s “This Week” on Sunday. He said that while the debate would be about foreign policy, “the most important thing we can do as a country on our foreign policy is strengthen our economy here at home.”

The president’s advisers argue that if Romney had been in charge, the United States might still be at war in Iraq, would have no end date in sight in Afghanistan and would not have made defeating Osama bin Laden the top priority.

Indeed, gearing up for the debate, Obama’s campaign charged Sunday that Romney had a “commitment to endless war.”

They have tied the cost of the wars — and Romney’s plan to spend $2 trillion more than Obama on defense in the next decade — back to the economy, by saying that would make the deficit worse or sap investments in rebuilding at home.&nbsp;

Tough, but Not Too Tough

Romney’s rhetoric has been sharper than the president’s, particularly in his views of the Middle East, which is expected to take up two-thirds of the allotted time tonight. But beneath the rhetoric, Romney’s policy prescriptions for Middle East hot spots don’t differ that much from what Obama is already doing.

Romney’s overall message — and a theme of his book “No Apology” — is that Obama has projected an image of weakness in the region, inviting political actors to challenge U.S. dominance.

There may be no more important debate than what consists of the “red line” for a U.S. military strike on Iran.

Romney has said repeatedly that he will prevent Tehran from acquiring nuclear weapons capability, as opposed to Obama’s pledge to prevent Iran from developing an actual nuclear weapon. But both refuse to say what Iranian action would trigger a U.S. military response. Romney has said his “red line” for Iran is the same as Obama’s and that he believes the confrontation with Iran can be solved without the use of force — a position that tracks with that of the administration.

The difference, according to Romney’s running mate Paul Ryan, is about having a credible threat of military force. “Under a Romney administration, we will have credibility on this issue,” the Wisconsin Republican said in the vice presidential debate.

A New York Times story, meanwhile, detailing talks between the United States and Iran that would take place after the elections, seemed to give some credence to the White House position that its policy on Iran of tough sanctions and engagement is working, although the White House denied that there was such a deal. But the presidents’ advisers on Sunday pointed to the plummeting Iranian currency under tough new sanctions this year as a sign the president’s policies are working, which they credited to Obama’s rallying the world against the Iranian regime.

Other Middle East hot spots are sure to get airtime tonight, including Israel, Syria and Libya.

In his bid to attract the country’s evangelical Christian voters and Jewish support, Romney has accused the president of “throwing Israel under the bus” on issues ranging from Iran to peace talks with the Palestinians. He also has said he would arm the rebels fighting to overthrow Syrian President Bashar-al Assad, and he says he would send a U.S. aircraft carrier into the eastern Mediterranean to bolster U.S. forces in confronting Iran.

Both support a transition to democracy in the wake of the revolutions that swept the region last year. But both are wary of Islamic extremists taking advantage of the political turmoil.

Obama’s efforts to restart peace talks between Israel and the Palestinians foundered when Israeli Prime Minister Benjamin Netanyahu refused to halt Jewish settlement construction in the West Bank. It is far from clear whether Obama would try to revive the peace process in a second term. In private, Romney has said he views the Israeli-Palestinian conflict as irreconcilable and would manage it as best as possible, as opposed to trying to resolve it. And Romney’s trip to Israel this summer infuriated Palestinians after he suggested the economic disparity between Israelis and Palestinians was due to “culture.”

Obama has adopted a cautious approach to the civil war in Syria, providing rebels there with non-lethal assistance, such as communications and medical equipment. But the administration is reluctant to provide the rebels with weapons because it can’t be sure whether they would end up in the hands of anti-Western Islamist fighters.

Like Obama, Romney has ruled out sending U.S. troops into Syria. And his willingness to arm the rebels is not so straightforward. He has said he would provide the weapons indirectly through Arab allies, such as Saudi Arabia and Qatar. Those countries are already arming the rebels, and U.S. officials monitoring the situation in Syria now say the bulk of those weapons are ending up in the hands of the Islamists.

On Afghanistan, Obama has said he will withdraw U.S. combat forces by the end of 2014. Romney’s position on Afghanistan has shifted over the past few years, beginning with support for a nation-building effort in 2009 to a more recent reconsideration of such policies. Today, Romney agrees with the administration’s timeline for withdrawal as a goal, but he criticizes Obama for announcing it publicly.&nbsp;

Libya

The attack on the U.S. consulate in Benghazi, Libya is also certain to come up again, giving Romney another chance to go after the administration’s response to the attack after he awkwardly misfired in last week’s debate. Romney’s surrogates in Congress in the past week have continued to charge the White House with repeatedly shifting its explanations on the attack in what they suggest may have been a bid to avoid spoiling the president’s tough-on-terrorism narrative highlighted by the killing of bin Laden.

However, leaks over the weekend of the CIA’s analysis backed up the administration’s early statements on the attacks. That could bolster Obama’s position, even as the release of the names of Libyan allies by Government Reform Chairman Darrell Issa’s (R-Calif.) gave Obama’s campaign another opportunity to blast the GOP with playing politics with national security.

Trade

Romney has also played offense on China and trade, arguing simultaneously that the Obama administration hasn’t been tough enough on China’s currency manipulation nor has he negotiated new free trade agreements with other countries. Obama has pointed to his administration’s repeatedly filing trade claims against China, in areas like auto parts and tires, and his campaign has repeatedly attacked Romney as someone who has benefited personally from companies outsourcing work to China through his investments at Bain Capital.

Romney also has faced criticism from his own party and supporters over his plan to label China a currency manipulator on “day one” and impose tariffs, with the business community fretting that a trade war could ensue that would hurt the economy more than help it.

But the get-tough-on-China message is one Romney’s campaign has pounded away at, especially in key states like Ohio, where polls have shown he continues to trail even as he has closed the gap nationally.

Obama has often pivoted on trade questions to tax policies, arguing to shift tax breaks from companies that ship jobs overseas to companies that bring jobs back to the United States.

The Romney rejoinder has generally been that Obama’s already had his chance to implement his policies, and it’s time for someone else.